While searching the skies above 18th century France for comets, astronomer Charles Messier [
http://www.seds.org…] diligently recorded this object as number 27 on his list of things which are definitely not comets [
http://antwrp.gsfc.…]. So what is it? Well, 20th century astronomers would classify it as a Planetary Nebula [
http://www.seds.org…] ... but it's not a planet either, even though it may appear round [
http://antwrp.gsfc.…] and planet-like in a small telescope. Messier 27 (M27) is now known to be an excellent example of a gaseous emission nebula [
http://www.astro.wa…] created as a sun-like star runs out [
http://antwrp.gsfc.…] of nuclear fuel in its core. The nebula forms as the star's outer layers are expelled into space, with a visible glow generated by atoms excited by the dying star's intense but invisible ultraviolet light [
http://imagine.gsfc…emspectrum.html ]. Known by the popular name of the Dumbbell Nebula [
http://www.seds.org…], the beautifully symmetric interstellar gas cloud is about 1,200 light-years away in the constellation Vulpecula [
http://hawastsoc.or…]. This intriguing color composite view [
http://www.ricksast…] was recorded through narrow band filters sensitive to emission from hydrogen atoms (shown in red) and oxygen atoms (shown in blue/green).
Explanation
While searching the skies above 18th century France for comets, astronomer Charles Messier [
http://www.seds.org…] diligently recorded this object as number 27 on his list of things which are definitely not comets [
http://antwrp.gsfc.…]. So what is it? Well, 20th century astronomers would classify it as a Planetary Nebula [
http://www.seds.org…] ... but it's not a planet either, even though it may appear round [
http://antwrp.gsfc.…] and planet-like in a small telescope. Messier 27 (M27) is now known to be an excellent example of a gaseous emission nebula [
http://www.astro.wa…] created as a sun-like star runs out [
http://antwrp.gsfc.…] of nuclear fuel in its core. The nebula forms as the star's outer layers are expelled into space, with a visible glow generated by atoms excited by the dying star's intense but invisible ultraviolet light [
http://imagine.gsfc…emspectrum.html ]. Known by the popular name of the Dumbbell Nebula [
http://www.seds.org…], the beautifully symmetric interstellar gas cloud is about 1,200 light-years away in the constellation Vulpecula [
http://hawastsoc.or…]. This intriguing color composite view [
http://www.ricksast…] was recorded through narrow band filters sensitive to emission from hydrogen atoms (shown in red) and oxygen atoms (shown in blue/green).
Explanation
